1. Field of the Invention
The present invention relates to refrigeration systems and, more particularly, to hydraulic refrigeration systems employing a hydrocarbon as a refrigerant.
2. Description of the Prior Art
The principle of entrapping and compressing air by movement of water, i.e., using a hydraulic air compressor or "trompe" has been employed industrially in the United States for some years. In one such installation, air is drawn into a down flowing stream of water and trapped within a cavernous underground chamber where the head of water maintains it under compression. The air may be permitted to escape through a pneumatic engine or turbine; thus, power may be generated.
In refrigeration systems, the major operating costs arise from the costs attendant energizing a mechanical compressor to compress adiabatically the refrigerant. Additionally, the cost of such a compressor is a substantial part of the initial cost of the refrigeration system itself. Thus, it would be beneficial from the standpoint of both initial and operating costs to eliminate the need for a mechanical compressor in a refrigeration system.
The use of CFC refrigerants, sometimes referred to by the trademark "FREON", is in the process of being legislated and taxed out of existence. These compounds, when leaked or dumped to the atmosphere, are thought to migrate to the stratosphere where destruction of the ozone layer is believed to occur. This layer is the earth's protection against the part of the radiation from the sun known as UV-B. An increase in UV-B radiation reaching the surface of the earth will cause increased incidence of skin and other cancer in humans and, if severe enough, interference with plant life and interruption of the earth's food chain.
An alternative family of compounds known as HCFC's are thought to cause much less ozone damage than do the CFC compounds but this is not certain; legislation is already underway against use of HCFC compounds. Nevertheless, the refrigeration industry is presently proceeding with new designs and manufacturing methods to produce refrigeration systems using HCFC compounds. This direction would appear to be an interim solution and not a permanent or desirable solution to the well recognized problem. Furthermore, conventional refrigeration systems using HCFC compounds are larger and less efficient than systems in current use with CFC compounds.
An additional alternative family of compounds known as HFC's are thought to do little or no damage to the ozone layer. The use of these compounds is still in the preliminary stages of experimentation and production. If these compounds prove feasible, they will require new system designs and manufacturing techniques. It is anticipated that these systems will be expensive and inefficient. Other conventional systems of refrigeration include absorption systems and systems using anhydrous ammonia as the refrigerant. For various reasons, these systems also are not suitable replacements for conventional systems using CFC compounds.
The family of liquid hydrocarbons are known to be excellent refrigerants except that they are flammable. It is not safe or feasible to use hydrocarbon refrigerants in conventional vapor compression refrigeration machines. Any leak would expel a pure flammable liquid. In the piping or conduits following the compressor, the refrigerant is at a temperature of several hundred degrees Fahrenheit and ignition of any leaking refrigerant would probably occur immediately upon leakage. Because of the relatively high pressures, intense vibration and pressure oscillations attendant conventional systems, some leakage within the system is almost guaranteed.